Solvent extraction of hydrocarbon oil



Patented Sept. 17, 1935 UNITED STATES SOLVENT EXTRACTION OF HYDROCARBON OIL Charles Frederick Teichmann, New York, N. Y., assignor to The Texas Company, New York, N. Y., a corporation of Delaware No Drawing. Application December 21, 1934, Serial No. 758,613

7 Claims.

CH CH3 I OH The foregoing solvent is suitable for extracting undesirable constituents from mineral oils and particularly from lubricating fractions.

Lubricating oils, such as produced from Mid- Continent crude, are ordinarily composed of relatively paraffinic constituents, and also relatively non-paraffinic constituents, including naphthenic, aromatic, and. unsaturated hydrocarbon bodies. The solvent of my invention is adapted to extract these relatively non-parafiinic bodies from the oil for the production of lubricating oil fractions which are of relatively high paraffinic character, and therefore of relatively higher viscosity index than the untreated oil.

In the application of my invention to the treatment of mineral oils for the production of lubricating oil, one part of the oil is mixed with about two parts of solvent liquid, and this mixture is then subjected to agitation and heating in order to effect solution of the undesired constituents of the oil in the solvent. The extent to which the oil is soluble in the solvent will de pend upon the nature of the oil as well as upon the conditions of temperature and pressure employed. The conditions of temperature and pressure, as well as the ratio of solvent to oil, may be varied for the purpose of effecting the particular degree of extraction desired. The temperatures employed, for example, may range from about 33 to 235 F. or thereabouts.

Upon settling, the mixture separates into two layers, one of which comprises the constituents which it is desired to extract from the oil dissolved in the bulk of the solvent liquid, while the other layer comprises the undissolved and relatively parafiinic oil inadmixturewith a relatively small amountof solvent.

The two layers are then separately withdrawn, and the solvent liquid recovered therefrom. If desired, the separated layers may be subjected to treatment with additional quantities of the solvent for the purpose of obtaining a series of fractions of differing characteristics.

In some instances, it may be of advantage to carry out the extraction in the pressence of a modifying solvent liquid, such as benzol, or a light petroleum naphtha, for the purpose of facilitating the extraction and further controlling the extent thereof.

The lubricating oil distillate may be subjected to the foregoing extraction treatment, either before or after dewaxing, or subsequent to treatment with other solvents or chemicals.

The invention is not necessarily limited to the treatment of lubricating oil fractions, since the solvent may be adapted to the refining and purification of various hydrocarbon or mineral oil fractions, including naphtha, cracked naphtha, kerosene, etc., as well as residual or distillate fractions, or products derived from petroleum or other sources.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. The method of refining hydrocarbon oil containing relatively parafiinic and relatively nonparafiinic constituents, including naphthenic, aromatic and unsaturated bodies, to remove undesired relatively non-parafiinic constituents therefrom, which comprises extracting the oil with carvacrol whereby the undesired constituents are separated from the oil as an extract soluble in the carvacrol.

2. The process for separating mineral oils containing naphthenic hydrocarbons into fractions which comprises bringing the oil into contact with carvacrol, thereby to effect solution of a portion of the oil richer in naphthenic hydrocarbons in the carvocrol, separating the solution so formed from the remainder of the oil and removing the carvacrol from both of the portions of the oil thereby to obtain fractions of the oil respectively richer in parafiinic and naphthenic hydrocarbons.

3. The method of refining hydrocarbon oil containing relatively paraffinic and relatively nonparafiinic constituents which comprises fractionally extracting the oil with carvacrol to produce fractions of the oil respectively richer in paraffinic and non-paraffinic hydrocarbons.

4. The method of producing a lubricating oil of high viscosity index from a lubricating oil fraction containing hydrocarbons of both high and low viscosity index which comprises extracting the lubricating oil fraction with carvacrol to remove therefrom hydrocarbons of low vis cosity index and to obtain a lubricating oil of high viscosity index.

5. The method of producing a lubricating oil of high viscosity index from a lubricating oil fraction containing hydrocarbons of both high and low viscosity index which comprises adding carvacrol to the lubricating oil fraction, heating the mixture to such temperature as to effect solution, cooling the solution to form a two layer system and separating the extracted oil layer from the carvacrol layer containing the extracted low viscosity index hydrocarbons.

6. The method of producing a lubricating oil of high viscosity index from a lubricating oil fraction containing high and low viscosity index constituents, which comprises extracting the lubricating oil fraction with a solvent liquid comprising carvacrol, forming an extract phase containing low viscosity index constituents of the oil dissolved in the solvent and a raffinate phase comprising high viscosity index constituents of the oil, and separating the two phases.

'7. The method of producing a lubricating oil of a high viscosity index from a lubricating oil fraction containing high and low viscosity index constituents, which comprises extracting the oil with a solvent liquid consisting of benzol and carvacrol, forming an extract phase containing low viscosity index constituents of the oil dissolved in the solvent and a raflinate phase comprising high viscosity index constituents of the oil, and separating the two phases.

CHARLES FREDERICK TEICHMANN. 

